1. Field of the Invention
This invention relates to an improved wafer-type swing check valve construction.
2. Prior Art Statement
It is known to provide a wafer-type swing check valve construction having a metallic housing body provided with an inlet and an outlet interconnected together by a valve seat that is adapted to be opened and closed by the effect of a pressure differential acting across a metallic valve disc pivotally mounted to the housing body by a pivot pin-like part of the valve disc that has opposed ends thereof rotatably received in cooperating recess means in the housing body so that the pivot pin-like part will pivot in the recess means as the valve disc is moved by the pressure differential relative to the valve seat.
For example, see the following five U.S. patents:
(1) U.S. Pat. No. 2,532,067--La Bour PA1 (2) U.S. Pat. No. 2,930,400--Wheatley PA1 (3) U.S. Pat. No. 3,933,173--Kajita PA1 (4) U.S. Pat. No. 4,054,153--Guyton PA1 (5) U.S. Pat. No. 4,128,111--Hansen et al PA1 (6) U.S. Pat. No. 3,825,030--Kalsi PA1 (7) U.S. Pat. No. 3,948,284--Walworth PA1 (8) U.S. Pat. No. 3,703,910--Smith.
It appears that the wafer-type swing check valve constructions of the above five items (1)-(5) each has the pivot pin-like part of the valve disc either fastened thereto or rotatably mounted thereto while being disposed in a recess means of the housing body, the check valve construction of item (4) above also appearing to have an annular groove provided either in the valve disc or the valve seat and receiving an annular flexible seal member therein to provide for a resilient seating arrangement between the valve disc and the valve seat while the housing body of item (2) above appears to have annular grooves in the coupling surfaces thereof for respectively receiving annular resilient members therein for sealing to cooperating coupling surfaces that couple the wafer-type swing check valve construction thereof in a fluid system.
It is also known to completely coat metallic valve members of the poppet-type, plug-type and the ball-type with plastic material to protect the same as well as completely line or coat the cooperating housing bodies therefor with such plastic material.
For example, see the following three U.S. patents: